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B.C.'s drought: Dry conditions spur changes to BCWS wildfire suppression tactics

Drought conditions and drier fuels mean wildfires can burn deeper.
A heat wave hits the hills in Kamloops.

This story is the second of a multi-part series running throughout June exploring the wide-ranging impacts of persistent drought conditions seen across the province since 2022.

With record low snowpacks and moisture levels priming much of the province for an active wildfire season, experts say drought conditions this year could make fire suppression more difficult for firefighters.

Mike Flannigan, a wildfire researcher at Thompson Rivers University, said drought conditions and drier fuels mean wildfires can burn deeper — especially in peatlands where organic material can reach 40 centimetres or more in depth — making them challenging to fight. 

“It means either digging, or if you're fortunate to have a significant water source, because basically, you have to flood it. You have to flood that area to put that smouldering fire out, or you get equipment,” Flannigan said.

“So it either costs you in time or money.”

Dry fuels are also more receptive to ignitions, Flannigan said. Whether a campfire or lighting strike ignites fuels, a wildfire is easier to start thanks to the little moisture.

How does BCWS respond?

Neal McLoughlin, superintendent of the predictive services unit at the BCWS provincial wildfire coordination centre, said the flammability of the landscape creates more aggressive fire behaviour, which requires firefighters to use indirect attack methods.

“That's where we might be building line, fire guard or defensive measures away from the fire and often parallel to the fire so that we're not in the the direction of the head fire spread,” McLoughlin said.

“We're trying to pinch it off from the sides [and] in the back as opposed to aggressively attacking the head.”

As fires burn deep under soils, McLoughlin said they will burn out root plates on trees. In order to safely avoid falling trees, BCWS will also spend more time clearing out hazards. 

“It increases the amount of time we need to spend, because we need to clear out those hazardous trees and make the fire line safe before our fire crews can work in that environment,” McLoughlin said.

He said the mop-up phase of wildfire suppression also takes longer, as wildfires take more resources to fully extinguish the edges of a blaze to ensure it doesn’t spread.

McLoughlin said longer mop-up periods can tie up crews, whether it be during a small initial attack fire or a larger incident with an incident management team. He said this can be a challenge when personnel resources are limited everywhere.

“In years like last year where we might lean on national and international resource exchange to help us with resource shortages, that can be challenging,” he said.

“We saw most of Canada was busy, and there was actually quite limited resource sharing opportunities at certain times of the season.”

Back burns and the 'Goldilocks problem'

Flannigan said planned ignitions — an emergency response method of indirect attack used to burn away fuels ahead of a fire — have become more commonplace in the last 10 to 20 years.

Planned ignitions have become more popular due to an acceptance that direct attack methods are less effective on large active fires, and because the tactic has proven itself as a useful method of removing fuels.

However, Flannigan said the conditions need to be right to be used.

“It's really a Goldilocks problem because if it's too wet you can't burn, if it's too dry, there's wildfires, you can’t burn — and so it's got to be just right,” he said.

McLoughlin said drought conditions play a role in determining if BCWS will use a planned ignition, and if the fire can be kept under control.

“They’re going to be looking at can we hold that back burn along some linear feature or some landscape feature and keep it suppressed along that edge, and then progressively burn back towards that wildfire event,” McLoughlin said.

“At certain levels, it could be unsafe to put more fire on the landscape, and so that would be considered.”

According to McLoughlin, BCWS will often steer active fires into old wildfire scars to slow or stop it from spreading. However, in extreme drought conditions, these patches of charred fuels can be ineffectual.

“Really anything that's native of carbon, any vegetative material, can be combustible under those extreme conditions,” he said.

“I've seen historic burns re-burn in subsequent years and burn to white ash.”

Prescribed burns

McLoughlin said BCWS can take advantage of the dry conditions as well, using the drier conditions to begin prescribed burning activities earlier.

He said this year, prescribed burns started taking place in late February and early March. In a typical year, they begin in April and May.

However, if conditions remain too hot or too dry, a prescribed burn may become unsafe. Additionally, resources may not be available to conduct the burn if they become tied up on an active wildfire incident.

“We can pursue opportunities to burn earlier in the season, and have longer windows to do more projects,” McLoughlin said.

“But then as the fire season kicks off, that window might close because we're having to shift our focus to responding to wildfires.”

What will 2024 look like?

According to McLoughlin, recent rainfall in May has put a damper on the spring fire season. He said 2024 has seen a below-average number of wildfires so far, but this could rapidly change. 

“If we trend back into more of a hot drying pattern, with the underlying conditions, we could turn around quite quickly in the course of like a week and a half,” he said.

“We could be having a very active fire season, and so we're really looking for substantive amount of rain through the month of June to pull us out of the conditions we have."

Flannigan said dry fuels can be found reaching a metre to a metre and a half in depth below the surface, which can lead to more wildfires overwintering and starting up again the following season,

“This year in particular, they are a real problem because there was so much area burned last year that they didn't have a chance to do mop up around the perimeter for all the hotspots,” Flannigan said.

“So drought cause overwintering, which couple of weeks ago, many of them were spreading actively into unburned forest.”